Inkjet printing has become a pervasive printing technology. Drop-on-demand (DOD) inkjet printing systems are relatively inexpensive and are capable of meeting high quality printing needs of the home or office. DOD printing systems include one or more arrays of drop ejectors provided on a DOD inkjet printing device, in which each drop ejector is actuated at times and locations where it is required to deposit a dot of ink on the recording medium to print the image. In addition to the drop forming mechanism (e.g. a heater or a piezoelectric structure) and the nozzle making up each drop ejector, there are also one or more ink feed holes through which ink from an ink source is provided to one or more drop ejectors. Thermal inkjet printing devices having several hundred or more drop ejectors per printing device, also typically include driver and logic electronics to facilitate electrical interconnection to the heaters.
Continuous inkjet (CIJ) printing systems provide high throughput printing that is well matched to commercial printing requirements. In CIJ a continuous pressurized stream of ink is emitted from one or more nozzles and broken up into droplets, which are either directed toward the recording medium to make ink dots as needed to print the image, or are directed toward a gutter for recirculation. Controllable drop breakoff can be provided, for example as described in U.S. Pat. No. 6,505,921, by pulsing heaters at intervals that control the drop size. Drops of different sizes are then directed (e.g. by an air stream, or by asymmetric pulsing of heaters on different sides of the nozzle) either toward the recording medium or toward the gutter. Like DOD printing devices, CIJ printing devices also typically include one or more ink feed holes, as well as driver and logic electronics for controlling the heaters.
In order to provide high resolution printing at low cost and high throughput, it is desirable to pack DOD nozzle arrays and ink feed holes at close spacing. Additionally, for CIJ printing devices it can be desirable to enable cross-flow for cleaning between ink feed holes (including cleaning of channels leading to nozzles) for improved long-term printing reliability. In such compact DOD and CIJ printing devices, fabrication challenges arise that can be difficult to achieve using conventional device geometries and fabrication methods
Therefore, it would be advantageous to devise novel printing device geometries and fabrication methods that enable achieving one or more of the following requirements:
1) providing fluidic connection to a plurality of closely spaced ink feed holes that are located near a nozzle array, either on the same side or on opposite sides of the nozzle array; and
2) providing reliably sealed fluidic connection of ink supplies to ink feed holes for two different color inks where the ink feed holes for the different inks are significantly less than 1 mm apart on the nozzle face of the printing device.